Post-thrombotic syndrome is a chronic disorder affecting 40%-48% of patients during the first 2 years after acute symptomatic deep venous thrombosis (DVT) (Ann Intern Med 2008 Nov 18;149(10):698). The American College of Chest Physicians currently recommends wearing compression stockings with 30-40 mm Hg pressure at the ankle for 2 years to reduce the risk of developing post-thrombotic syndrome (ACCP Grade 2B, Chest 2012 Feb;141(2 Suppl):e419S, full-text). However, the data supporting this recommendation are inconsistent, and come from small randomized trials without blinding. A new double-blind randomized trial compared compression stockings to sham stockings (without therapeutic compression) in 806 patients with proximal DVT.

Patients (mean age 55 years) with first-time symptomatic proximal DVT were randomized to elastic compression stockings with ankle pressure 30-40 mm Hg vs. sham stockings with ankle pressure < 5 mm Hg. They were instructed to wear their assigned stockings daily during waking hours for 2 years. Stockings were worn as pairs applied within 2 weeks of presentation with DVT, and were replaced every 6 months, or earlier if stockings were torn or a patient’s leg size had changed. Patients with a short expected lifespan (< 6 months) and those who had received initial treatment with thrombolytic therapy were excluded from the trial. Post-thrombotic syndrome was assessed using Ginsberg’s criteria (leg pain and swelling for ≥ 1 month). The development of post-thrombotic syndrome was assessed every 6 months.

The overall proportion of patients adhering to use of stockings ≥ 3 days/week was 86.4% at 1 month (83.8% with compression vs. 89.1% with sham) and 55.6% at 2 years (56.1% with compression vs. 54.8% with sham). After excluding 3 patients found to be ineligible after randomization, 803 patients were included in the primary efficacy analysis. The cumulative incidence of post-thrombotic syndrome was 14.2% with elastic compression stockings vs. 12.7% with sham stockings (not significant). These results were consistent in a per-protocol analysis evaluating only patients reporting any stocking use on ≥ 2 visits and using stockings ≥ 3 days/week at those visits. There were no significant between-group differences in post-thrombotic syndrome severity, frequency of ipsilateral leg ulcers, or quality of life scores.

The findings of this new trial do not support routine use of compression stockings following acute DVT for prevention of post-thrombotic syndrome. These new results are not consistent with previous findings, although this is the largest trial to date to evaluate compression stockings in this patient population, and the only one thus far to have a blinded assessment using a sham stocking as a comparator. The adherence to compression stockings in this trial is reported to be lower than those observed in previous trials, although differences in methods used to measure adherence make any direct comparisons difficult. In addition, stockings may lose their elasticity after about 3 months (Circulation 2004 Oct 19;110(16):e445full-text), so the decision to replace stockings every 6 months in this new trial may have resulted in suboptimal therapeutic compression.